1) Field of the Invention
The invention herein relates to a various electrical characteristics and small test point testing module, specifically a kind capable of testing the various electrical characteristics of a range of electronic products that provides for high testing density, even lighter testing pressure, and stabler testing results. Furthermore, the present invention can be utilized as a testing module for testing different blank circuit boards or component mounted boards.
2) Description of the Prior Art
The methods for conducting tests of conventional electronic product-use circuit boards typically includes the following examples:
As indicated in FIG. 1 and FIG. 2, the prior art consists of an apparatus 1 base 11 having a needle plate 12, a clamp plate 13, a top plate 14, and a plurality of probes 2, wherein the said needle plate 12 needle holes 121 are aligned with the test points 31 of a tested object 3 (such as a printed circuit board); the said plurality of probes 2 each consisting of a probe barrel 21, a needle tube 22, a spring 23, and a needle body 24.
The said probe 2 probe barrel 21 is inserted into a needle hole 121 at a predetermined position on the needle plate 12 and a lead 4 is disposed at one end for signal transmission to a testing instrument (not shown in the drawings); the said spring 23 is contained inside the needle tube 22, the needle body 24 is inserted into the needle tube 22, the compression and decompression of the spring 23 enables the needle body 24 to elastically extend from and retract into the needle tube 22, and the said needle tube 22 is affixed within the probe barrel 21; as such, the said probe 2 can be completely positioned on the needle plate 12.
The said clamp plate 13 and top plate 14 each have insertion holes 131 and 141 that are aligned with the needle plate 12 needle holes 121 such that the needle bodies 24 inserted into the clamp plate 13 and top plate 14 insertion holes 131 and 141 protrude at the top plate 14.
As such, the tested object 3 is placed on the upper extent of the top plate 14, the tested object 3 test points 31 and the probe 2 needle bodies 24 are brought into contact, then the said electrical signal is sequentially transferred via the springs 23, the probe barrel 21, and the leads 4 connected at the probe barrel 21 bottom section to the testing instrument, thereby completing the testing operation.
Given the said arrangement, the prior art testing apparatus has the following drawbacks:
1. When the probe 2 contacts the tested object 3 test points 31, an elastic rebounding, compressive-decompressive force is required to prevent electrical damage to the test points 31 and, as a result, the needle body 24 relies on a spring 23 for withdrawal into the needle tube 22 such that the needle body 24 is automatically retracted elastically after compression and given such a structural arrangement, the entire probe 2 cannot be fabricated smaller or when fabricated smaller, the relative cost is very high, resulting in a cost increase and an inability to raise testing density.
2. Since the probe barrel 21 must be designed to match the dimensions of the probe 2, the dimensions are subject to limitations to the extent that the overall distribution density of the needle plate 12 needle holes 121 cannot be increased, resulting in an incapability to test high density testing point 31 tested objects 3.
3. Since the transferred signal of the tested object 3 testing point 31 results from the assembly and electrical contact of the needle body 24, the spring 23, the needle tube 22, and the probe barrel 21, poor and weak signal transmission results following numerous contacts and transfers that adversely affects testing quality, which become even more deteriorated when testing high density test points.
4. The probe 2 contacts the tested object 3 vertically and, as a result, the tip distance d of the adjacent probe 2 needle body 24 cannot be further reduced such that testing operations on tested objects 3 having small test points (i.e., test points 31 distributed at a higher density) cannot be accomplished.
In view of the said situations, manufacturers introduced the testing apparatus shown in FIG. 3 and FIG. 4 that consists of needle plates 5, lead plates 6, a plurality of linear probes 7, and a plurality of elastic components 8 disposed on the said apparatus, wherein the said needle plates 5 and lead plates 6 are in a stacked assembly, the said needle plates 5 consist of a plurality of guide correction plates 51 and a top plate 52, and the top plate 52 has the insertion holes 521 of the test points 31 of the tested object 3, and the said guide correction plates 51 have top plate insertion holes 521 that are aligned with the insertion hole 511; the said lead plates 6 consists of an upper layer, a middle layer, and a lower layer clamp plate 61, 62, and 63, with each having insertion holes 611, 621, and 631 drilled in them that are aligned with the guide correction plate insertion holes 511 of the needle plate 5, wherein the said middle layer clamp plate 62 insertion holes 621 contain an elastic component 8 and the said lower layer clamp plate 63 insertion holes 631 provide for connecting a inserted lead 4 between a testing instrument (not shown in the drawings) and the lower end of each elastic component 8; the said linear probes 7 are inserted along the needle plate 5 top plate insertion holes 521, the guide correction plate insertion holes 511, and the lead plate 6 upper layer plate 61 insertion holes 611, with their inner extremities postured against the elastic component 8 and the outer extremities exposed at needle plate top plate 52.
As such, the tested object 3 is placed on the upper extent of the needle plate 5 top plate 52 and since the testing instrument linear probes 7 and the test points 31 of the tested object 3 are brought into contact, the said electrical signal is sequentially transferred through the elastic components 8 and the testing instrument leads 4 to complete a testing operation.
Given the arrangement of such a testing apparatus, although the assembly of the probe needle body 24, spring 23, needle tube 22, and probe barrel 21 first required of the prior art is simpler in terms of method, the said angular placement of the linear probe 7 can be utilized for tested objects 3 having test points 31 distributed in a higher density and the prior art apparatus thus has an even larger scope of application. However, since electronic product volume is becoming more and more compact, requiring a testing density that is even higher, a testing pressure that is even lighter, and greater testing stability, under these conditions, such testing apparatus still have the following drawbacks:
1. After the linear probes 7 are respectively inserted vertically or angularly into the needle plate 5 such that their inner extremities are situated against the aligned elastic components 8, the height of their outer extremities are not equal (the outer extremities of vertically inserted probes are higher and the outer extremities of angularly inserted probes are lower), when the tested object 3 is subjected to pressure, the linear probe 7 contact pressure with the test points 31 changes, the tested object 3 is easily damaged due to unequal pressure, and testing is not stable, which are the prior art drawbacks most often criticized by manufacturers.
2. Since each linear probe 7 requires a matching elastic component 8 and, furthermore, the linear probe 7 is extremely small and the said elastic components 8 must be proportionately smaller; utilizing numerous small elastic components, in addition to troublesome fabrication and assembly, inconvenience, and high cost, the individual alignment of linear probe 7 elastic force often results in unequal linear probe 7 spring force, resulting in unequal testing pressure against tested object 3 test points 31 and testing instability.
3. Since the signals of the said linear probes 7 from the tested object 3 test points 31 must pass through the medium of the elastic components 8 before transfer to the testing instrument via the leads 4, the transmission of the said test signals is still poor and weak because there are too many connection points, which adversely affects testing quality and stability.